2023-06-30 09:50:11
Galaxies are the fundamental building blocks of the large-scale structure of the universe, and they draw a sponge-like network that shows dense clusters, filaments, sheet walls and very sparse regions, known as cosmic voids.
These voids constitute the least dense regions of the universe, since they occupy around 80% of its volume and contain only 10% of its mass. An international team has published in Nature and job which shows that the galaxies that inhabit these voids evolve more slowly than the rest.
Previous studies had shown that void galaxies exhibit, on average, properties that correspond to younger and less evolved systems than filament, wall, and cluster galaxies. However, it had never been observed observationally that there was evolutionary differences between each other.
Scientists have managed to estimate for the first time the speed at which galaxies in cosmic voids form stars throughout their history.
With this purpose, the CAVITY project was born, headed by the University of Granada, developed from the Calar Alto Observatory and in which the Institute of Astrophysics of Andalusia (IAA-CSIC) participates.
The CAVITY team has succeeded in estimating, for the first time, the speed at which galaxies in cosmic voids form stars throughout their history, as well as the role that the large-scale structure of the universe plays in the evolution of galaxies.
This is the first statistically significant study on the evolution of galaxies in the different large-scale structures of the universe, with data from about ten thousand galaxies located in voids, filaments, walls, and clusters.
Simulation of the large-scale structure of the universe, showing dense clusters of galaxies, filaments, shell walls, and voids. / Project Uchuu.
The scientific team has been able to estimate the ages and masses of the stars that make up these galaxies and describe their star formation storywhich has revealed that galaxies in voids evolve more slowly than galaxies with denser structures.
In addition, they have found that the first galaxies that formed in the universe evolved at the same speed regardless of the structure where they are now.
Initial conditions of the universe
However, about eleven billion years ago, when the universe was 2.8 billion years old, the evolutionary histories of galaxies began to unfold. divergewhich indicates that in the early stages of the universe the large-scale structure might not have been so defined as to generate differences in the evolution of the galaxies that formed then, but it was in later stages.
This large-scale structure is the result of the evolution of the universe from the Big Bangand the study of the current distribution of galaxies and their properties allows us to rewind time and obtain information about the initial conditions of the universe.
Researchers have been able to calculate the ages and masses of the stars that make up these galaxies and describe their star formation history.
The high density of filaments and clusters accelerates and alters the characteristics of galaxies, but voids are quiet environments of slow evolution that can shed light on the initial conditions of the universe.
“These results are based on the analysis of the integrated spectra of the central zone of the galaxies, an area of great relevance although small in size. We are collecting data in Calar Alto with a spatial resolution that will allow us to explore both the global and local properties of the galaxies residing in these cosmic voids.” Ruben Garcia-BenitoIAA-CSIC researcher who participates in the work and in the CAVITY project.
Reference:
J. Dominguez-Gomez et al. “Galaxies in voids assemble their stars slowly”. Nature(2023)
Rights: Creative Commons.
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